The present invention relates to a device for filling spacer frames for insulating glass with hygroscopic material.
Said spacer frames usually comprise hollow profiled bars which are usually joined at one or more corners by means of angles made of plastics or metal.
Said frames thus have a first wall lying externally to the insulating glass, a second wall arranged inside the insulating glass, and two third lateral walls arranged adjacent to the glass sheets that form the insulating glass.
Hygroscopic material must be poured inside the spacer frames, and adapted holes are formed at the second inner wall so as to maintain the required degree of humidity inside the insulating glass.
For this purpose, it is known to manufacture spacer frames which are appropriately folded on three sides, leaving the ends adjacent at one corner disconnected and particularly so that one of the two ends is not folded and thus protrudes beyond the perimetric edge of the other one.
This allows to load the hygroscopic material on two sides of the frame, i.e. al the sides whose ends are free: once this operation has been performed, one of the two ends is folded and connected to the other by means of an adapted metal or plastic insert.
However, this method has considerable drawbacks: first of all the frame is loaded with hygroscopic material only at two of its four sides and after filling it is furthermore necessary to perform additional work steps that can for example cause the accidental loss of part of this hygroscopic material.
As a partial solution to these drawbacks, it is known to manufacture frames that are again folded so as to form a geometrical shape that is open at one corner; an L-shaped closing insert can be associated at the free ends.
The hygroscopic material is again loaded before assemblying the L-shaped insert; however, even this solution has the drawbacks mentioned above and thus allows to fill the frame with hygroscopic material only on two sides, with the additional drawback due to the difficulty of hermetically sealing the frame at the corner even when it is sealed with a local injection of butyl.
Furthermore, should one wish to fill each individual side of the frame with hygroscopic material, the frame would have to be formed by multiple elements that were subsequently mutually associable by using angular inserts that allow coupling to the following side.
Even this solution, however, would not be optimum, since on one hand it would not be possible to seal the frame hermetically at its corners, even by injecting butyl locally, and furthermore there would be an excessive time interval between the loading of the hygroscopic material and the coupling of the frame to the glass sheets.
Furthermore, an excessive manual work would be required to assemble the composite frame, i.e. a frame whose sides are joined at their ends by means of angular inserts.
Italian patent no. 1190881, filed on Jun. 22, 1982 as application no. 21991 A/82, is also known among the known art: this patent discloses a device for filling spacer frames with hygroscopic material, whose purpose is to allow the final and permanent filling of spacer frames which are already folded and thus closed.
This is achieved by means of a device that forms an opening in the outer wall of the spacer frame; the hygroscopic material is introduced through this opening, which is sealed by means of a welding tip.
However, even this solution has drawbacks due to the use of multiple devices, including a welding machine which has considerable problems since welding must be performed on a frame having a very limited thickness.
Accordingly, there is the problem of hermetically welding this hole, also bearing in mind that any application of material alters the flatness of the outer surface of the frame, which must be maintained as much as possible in order to subsequently apply sealant optimally.
As a partial solution to this drawback one might think to form a seal, at the hole formed on the outer wall of the frame, not with a welding machine but for example with butyl; however, this solution would in any case have drawbacks, due to the difficulty of sealing the hole at its thickness, unless an overabundant amount of sealant (which depends anyway on the size of the profile) is injected or unless holes provided with a collar are formed with great difficulty.
There is accordingly the risk of not achieving frame flatness at the injection hole formed on the outer wall.
A discontinuity would also be produced on said outer wall of the frame, on which a second seal must be subsequently performed, and this would entail discontinuities and problems in applying the bead of sealant at the opening.
It is also known to manufacture a frame in a closed shape, on which holes are subsequently produced at the side walls which are then arranged adjacent to the glass sheets forming the insulating glass.
Even this solution has drawbacks, since there is still the problem linked to the need to seal said holes, with the consequent observed presence of discontinuities during the application of the first seal, if provided; these discontinuities are worsened when the side walls provided with the holes must be pressed at the glass sheets forming the insulating glass.
In fact it has been observed that during the application of the sealant said sealant may become interrupted at the hole, causing the frame to be no longer hermetically sealed.
It should in fact be noted that the frame must be permeable to air only at the wall lying inside the insulating glass.